Two Roman forts have been found by archaeologists at Dinefwr, the National Trust-owned park, in Llandeilo, South Wales.

Members of Cambria Archaeology made the incredible discovery whilst carrying out a commission for the National Trust to survey the park and gain a better understanding of the archaeological importance of the area.

A combination of geophysical surveying and aerial photography has revealed what experts believe could be the largest fort in Wales outside the regional Roman headquarters at Caerleon, as well as a smaller, later military construction.

Gwilym Hughes, Director of Cambria Archaeology told the 24 Hour Museum how the Romans built forts in South Wales at set intervals. He explained that, with one at Llandovery and Carmarthen either side of Llandeilo, he and fellow archaeologists have long suspected there might be one near the town.

“It's quite amazing,” said Mr Hughes. “We've always suspected there was a fort in Llandeilo, there had to be one here and it was nice to be vindicated!”

As Mr Hughes explained, this fort, like others in South Wales, was probably built in around 70 AD shortly after the invasion in an attempt to subdue the local population.

It is believed to have been a campaigning fortress where a large military detachment would have been posted. Such a large presence in the area suggests a greater resistance to the Roman invasion of Wales than was previously thought.

It seems, however, that the need for reinforcements to bolster campaigns elsewhere probably forced the abandonment of this larger fort. When the area was subsequently reoccupied, a smaller fort packed with buildings and streets was built on the same site.

“It is one of the best geophysical surveys I've seen, if not the best,” said Mr Hughes. “To have all this without having to put a spade in the ground is quite fantastic.”

The survey was made possible with a grant from the Heritage Lottery Fund and it is hoped that further archaeological work can be carried out later in the year.

“This just happens to be on a Grade I listed landscape,” added Mr Hughes. “It has got everything, it's an amazing piece of parkland, so this fort is yet another jewel in their crown.”